Brian F. Allen

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Dynamic simulation is a promising complement to kinematic motion synthesis, particularly in cases where simulated characters need to respond to unpredictable interactions. Moving beyond simple rag-doll effects, though, requires dynamic control. The main issue with dynamic control is that there are no standardized techniques that allow an animator to(More)
Fluid bipedal locomotion remains a significant challenge for humanoid robotics. Recent bio-inspired approaches have made significant progress by using small numbers of tightly coupled neurons, called central pattern generators (CPGs). Our approach exchanges complexity of the neuron model for complexity of the network, gradually building a network of simple(More)
The size of crowds that modern computer games and urban simulations are capable of handling has given rise to the challenging problem of debugging and testing massive simulations of autonomous agents. In this paper, we propose SteerBug: an interactive framework for specifying and detecting steering behaviors. Our framework computes a set of time-varying(More)
We introduce a toolkit for creating dynamic controllers for articulated characters under physical simulation. Our toolkit allows users to create dynamic controllers for interactive or offline use through a combination of both visual and scripting tools. Users can design controllers by specifying keyframe poses, using a high-level scripting language, or by(More)
We present a technique that simulates wet garments for virtual humans with realistic folds and wrinkles. Our approach combines three new models to allow realistic simulation of wet garments: (1) a simplified saturation model that modifies the masses, (2) a nonlinear friction model derived from previously reported, real-world measurements, and (3) a wrinkle(More)
Precise control with proportional-derivative (PD) control generally requires stiffness. The proposed method determines critically damped PD control trajectories that precisely obtain target position and velocity constraints for arbitrary initial conditions. An analytic solution provides the PD control parameters, thereby determining the required impedance.(More)
We propose a method for accurately tracking the spatial motion of standard laparoscopic instruments from video. By exploiting the geometric and photometric invariants common to standard FLS training boxes, the method provides robust and accurate tracking of instruments from video. The proposed method requires no modifications to the standard FLS training(More)